In recent years, the number of tool intervention operations in wells has increased, and hydrocarbon wells are therefore made without electrical lines running inside the casing which may conflict with intervention tools. Some designs insert an inner string into the completion where the electrical conductors run on the outside of the inner string. Consequently, the inner diameter of the completion is thereby substantially reduced which is not desirable. The inner diameter is decreased when providing electricity downhole by means of the inner string solution, and in order to compensate for that and have a well design with an unchanged inner diameter, the overall diameter of the well has to be enlarged accordingly. Consequently, the costs of the completion increase substantially, which is also not desirable.
However, electricity is still needed for powering electrical devices arranged inside or outside the casing several kilometers down, as the completions become more and more developed, and this conflicts with the importance of keeping the casing free of electrical lines without breaking the main barriers of the well while obtaining an inner diameter which is as large as at all possible so that the production is kept efficient.